Dam Design and Construction

Executive interview: Facing the “tension between water operations and maximum generation”

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Executive interview: Facing the “tension between water operations and maximum generation”
(photo courtesy Denver Water)

Tom Roode is chief of operations and maintenance with Denver Water, the largest and oldest water utility in Colorado. Founded in 1918, Denver Water operates a system of reservoirs networked by tunnels and canals that provides water to 1.5 million people in Denver and surrounding suburbs. Money from the sale of the power produced by its seven hydroelectric plants is used to offset operating costs.

Roode joined Denver Water in 2009, and his group is responsible for operating and maintaining the physical and natural assets used to deliver water to customers, including rivers, canals, reservoirs, dams, tunnels, pipelines, valves, hydropower, tanks, pump stations and treatment plants. Operations and maintenance establishes and implements criteria for the proper operation of all assets to the satisfaction of outside regulating agencies and Denver Water customers.

Denver Water is host utility for HYDROVISION International 2024.

In this exclusive interview, Roode discusses the how the company achieves its goals of delivering water and maintaining a reliable and resilient system while facing challenges around rising O&M costs, attracting and retaining the next generation of the workforce, and the “tension between water operations and maximum generation.”

Q: Please give our readers a general overview of Denver Water, including your hydroelectric facilities.

Roode: Denver Water has 10 hydropower units operating at eight locations that take advantage of elevation changes in both raw and treated water systems to generate electricity. Our first hydroelectric unit was installed in 1959 at Williams Fork reservoir and is still in operation today. Other units are located in the headworks of our water treatment plants (two), dams (seven) and our treated water distribution system (one). Denver Water generates about 62 million kilowatt-hours of electricity annually and uses this energy to offset our energy consumption and as a revenue source when excess energy is sold to local utility partners.

Q: You’ve been chief operations and maintenance officer of Denver Water since 2011. What is your vision for the future of this organization?

Roode: My vision is represented through the Denver Water Strategic Plan Mission Statement, which is “To serve our customers by being a national leader in delivering clean water, operating and maintaining a reliable and resilient system, and protecting the water resources of the West.” The future has never been more uncertain in terms of changing climate, changing customer and workforce demographics, and increasing economic challenges. However, I have faith in the passion and adaptability of our teams to deliver on this mission.  

Q: How does being a water utility and public agency influence Denver Water’s work and direction?

Roode: I’d highlight two key aspects of this that make our organization special. The first is that our workforce are customers too, serving their families, friends and neighbors with high-quality water all the time. They take great passion in our mission, and it shows in their performance. The second is that we are an entity that should be around in perpetuity and, therefore, we get to take the long-term view in terms of providing good service at the lowest cost. This allows us to invest in long-term efforts to ensure our resiliency not just for our generation, but also future generations.

Q: Denver Water is in the midst of raising the height of Gross Dam. Can you give us an update on this project?

Roode: Denver Water’s Gross Reservoir Expansion Project will raise the height of the existing Gross Dam by 131 feet, creating a 471-foot-tall concrete arch dam and tripling the water storage capacity of the reservoir. This will make the new Gross Dam the tallest dam in Colorado and the tallest concrete dam built in the U.S. in the past 50 years.

Construction began in April 2022, and over the past two years, our team has excavated both foundation abutments, placed preparatory foundation concrete, grouted the foundation, completed hydro-demolition of the dam face, and completed a full-scale roller-compacted concrete trial placement. In short, the preparatory work is complete, and the project is on track to start the dam raise in the spring of 2024.

In addition to the dam foundation work, we constructed site offices, maintenance buildings and a materials testing lab; assembled the on-site crusher and batch plants; and have developed an on-site quarry. The team also rebuilt the intersection of Highway 72 and Gross Dam Road and improved several miles of Gross Dam Road to facilitate safe travel for the cement and fly ash truck deliveries scheduled for 2024 and 2025 during the dam raise.

The dam raise is expected to last two construction seasons between 2024 and 2025. In 2026, the spillway, dam crest, outlet works and hydropower modifications will take place, and in 2027 the site will be reclaimed, and the reservoir will begin the first filling process.

Working in close proximity to the public, maintaining an operational facility (including hydropower generation and on-water recreation), and working through the winter months is challenging, but it is made possible by a dedicated team from Denver Water and our contracting partners.

Q: What does the term “modern hydropower” mean to you?

Roode: To me it means the application of the distributed renewables model to hydropower and looking at all sources of flowing water as having potential energy. Over the past 10 years, Denver Water has invested in upgrading many of our hydroelectric plants and installed the latest technology to improve operations, condition monitoring, efficiency and control of our units. Northwater Treatment Plant’s new hydroelectric unit (which HYDROVISION attendees will have an opportunity to tour) is a good example of this.

Q: What is the main challenge for your hydropower facilities or portfolio?

Roode: Rising operational and maintenance costs coupled with contractor availability present challenges for Denver Water’s portfolio. Being that Denver Water operates our system to deliver treated water to our customers, hydropower generation is a secondary output, and we have relatively small units. Depending on mountain snowpack and other conditions in any given year, we may not be able to optimize our generation.

Q: What is the most striking change you have witnessed for hydropower recently?

Roode: Changes in the regulatory environment are putting a greater financial burden on dam owners and contributing to rising operational costs at our facilities. And advances in technology allow for more streamlined and efficient monitoring and remote control of hydropower units.

Q: You are speaking during the keynote session at HYDROVISION International 2024 in July. Can you give us some insight into a couple of the hot topics for Denver Water that you plan to cover?

Roode: I think I’d start with the challenges first, including things like the tension between water operations and maximum generation. Also, something that applies to many industries is the next-generation workforce. Are we going to be able to attract and train the next generation of operators and maintenance experts to care for our hydropower facilities? I can also share our experience with our Northwater treatment plant, which has the capability to be fully powered through hydropower, resulting in a net-energy-producing water treatment plant. I can also share some success stories and lessons learned through our Gross Dam project.

HYDROVISION International 2022

Q: Any final comments/thoughts on the future of hydropower?

Roode: We are always looking for new and innovative ways to increase our renewable energy portfolio and have partnered with both private sector and government entities to pilot new technologies. We look forward to continuing to build on these partnerships and help move the industry forward.